1. Field of the Invention
This invention relates to a branched fractal three dimensional porous polymer species which comprises rigid aromatic recurring units having electrophilic or nucleophilic reactive moieties on the exterior thereof. Another aspect of this invention relates to a star polymer comprising a polymeric core formed of the fractal polymers (FPS) of this invention having linear polymeric moieties grafted to the exterior thereof by way of residues formed by reaction between the reactive moieties on the exterior of the fractal polymer (FP) and complimentary reactive moieties on a linear polymer. Yet another aspect of this invention relates to polymeric composites comprising a polymer matrix having dispersed therein the star polymers of this invention.
2. Description of the Prior Art
Aharoni et al. Macromolecules, Vol. 23, No. 9, pg. 2533 (1990) describes the preparation of rigid and flexible polymeric networks and their gels by the reaction of aromatic diamine monomers (BB monomers) with aromatic or aliphatic diacid monomers (AA monomers).
Aharoni, S. M., Macromolecules, Vol. 24, No. 1, pg. 235 (1991), discloses that the formation of crosslinked networks takes place between fractal polymers whose surfaces are decorated by A and B reactive groups and may take place in the absence of all monomeric or low molecular weight species, by the direct reaction of the fractal polymers under appropriate reaction conditions. When the fractal polymers are made from AB monomers, then their exteriors are decorated by only one kind of reactive group, either A or B, and may not react with each other to form crosslinked networks. AB monomers are divalent or polyvalent monomeric species containing either one A group and one or more B groups, or, one B group and one or more A groups.
Conceptually similar structures, called starburst or dendimer polymers are described in Tomalia, et al, Angew, Chem. Intern. Ed. Engl., 29, 138 (1990), U.S. Pat. No. 4, 289, 872 and Hawker and Frechet, Macromolecules, 23, 4726 (1990). All these are tedious stepwise reactions which require at each growth step the preparation of protected or unreactable groups on the growing substantially aliphatic, branched species.